Legend:

By default, FOAM treates each VLAN as exclusive, unless a FOAM admin has added the VLAN to the list of reserved or shared VLANs. (A VLAN can be on both lists, although there's not really any reason to do that; but if you want to change a VLAN from one to the other, for example, you need to both remove it from the old list and add it to the new one.)